Glycerine is a clear, thick, sweet-tasting liquid used to hold moisture in skin and tissue. In the pharmacy it appears in moisturisers, in throat and mouth preparations, in ear drops, and in suppositories for constipation. It is not a drug — it works by attracting and holding water.
What is Glycerine?
Glycerine — also spelled glycerin, and known chemically as glycerol — is a pharmaceutical and cosmetic base ingredient rather than a medicine in its own right. It is sold in pharmacies as a plain liquid, usually as a general-sale item.
Because it is an ingredient rather than a scheduled medicine, plain glycerine is not listed in its own right in the South African Medicine Price Registry. It appears there only as a component of registered products — for example in Otised ear drops, an S1 preparation combining glycerine with benzocaine and phenazone.
Glycerine is a humectant. Its molecule attracts water and holds onto it. Applied to skin, it draws moisture from the deeper layers and from the air and keeps it in the surface layer, which is what makes dry skin feel supple rather than tight. Applied to mucous membranes — mouth, throat, gums — it forms a soothing film. Taken by mouth or given rectally in bulk, that same water-attracting property pulls water into the bowel.
One property is worth knowing before use: glycerine is hygroscopic, meaning that undiluted, it can pull water out of tissue rather than into it. This is why glycerine is nearly always used diluted or blended into a formulation, and why neat glycerine can sting or feel drying on sensitive or broken skin.
It is also sweet, which is why it appears in cough and throat preparations, and non-toxic in ordinary use, which is why it is so widely used in food, cosmetics and medicines alike.
What is Glycerine commonly used for?
On the skin:
- Dry skin, chapped hands and cracked lips, usually as a component of a cream, lotion or lip product.
- Cracked heels and rough elbows, often mixed with water or rosewater as a traditional home remedy.
- Softening skin before removing a dressing or a crust.
- Nappy area care and general moisturising, within a formulated product.
In the mouth and throat:
- Sore throat, in gargles and throat preparations — the film soothes rather than treats.
- Dry mouth, in artificial saliva products.
- Mouth ulcers and sore gums, in gels and mouthwashes.
- Cough mixtures, where it is both a soother and a sweetener.
Elsewhere:
- Constipation, as glycerine suppositories, which draw water into the rectum and stimulate emptying — usually within an hour.
- Softening earwax, in drops.
- Hydrating the eye surface, in some lubricating eye products.
As a formulation ingredient, holding water in creams, ointments and syrups, and keeping them from drying out.
What glycerine does not do is treat anything. It has no antibacterial, antifungal or anti-inflammatory action. It is comfort and moisture, and that is genuinely useful — but a dry, itchy rash that is actually eczema, or a sore throat that is actually a bacterial infection, needs a medicine rather than a soothing film.
How Glycerine fits into this medicine category
| Group | Examples | What it does |
|---|---|---|
| Humectants | Glycerine, urea, hyaluronic acid | Attract and hold water in the skin |
| Occlusive emollients | Emulsifying ointment, white soft paraffin | Seal moisture in with a physical barrier |
| Topical steroids | Betamethasone (Clomaderm) | Reduce inflammation in eczema and dermatitis |
| Antifungals | Clotrimazole (Canex V) | Treat fungal skin infection |
| Antiseptics | Chlorhexidine, povidone-iodine | Reduce bacteria on skin |
| Osmotic laxatives | Glycerine suppositories, lactulose, macrogol | Draw water into the bowel |
Humectants and occlusives work best together — one brings water into the skin, the other stops it leaving. That is why most good moisturisers contain both. See the skin and wound care hub.
What to check before using Glycerine
- Dilute it, or use a formulated product. Neat glycerine on skin can sting and, in dry air, may leave skin feeling worse rather than better. A common home approach is glycerine mixed with water or rosewater, roughly one part to three.
- Check what you have bought. Pharmacy glycerine intended for human use is not the same as industrial or craft glycerine. Buy a product intended for skin or medicinal use, from a pharmacy.
- Do not apply it to open wounds, burns, weeping or broken skin without advice.
- Do not put plain glycerine in the ear unless it is a product intended for that. Never use ear drops of any kind if you have or might have a perforated eardrum, ear surgery, or discharge from the ear.
- Do not put plain glycerine in the eye. Use only products formulated as eye drops.
- Patch test on a small area if you have sensitive skin.
- For suppositories, follow the pack instructions, and do not use them regularly for more than a few days without advice.
- Take care with diabetes, where glycerine taken in quantity by mouth can affect blood sugar, and where dry, cracked skin — especially on the feet — should be assessed rather than only moisturised.
- Store it sealed. It absorbs water from the air.
Possible cautions and when to ask a pharmacist or doctor
Glycerine is one of the safest substances in the pharmacy. Problems are unusual and mostly local: stinging, redness, irritation or a drying sensation, particularly when it is used neat or on sensitive skin.
Glycerine suppositories commonly cause mild rectal irritation, cramping or an urgent feeling, which settles quickly.
Stop and seek advice if skin becomes more irritated, red or itchy after use.
Get emergency help for swelling of the face, lips or tongue, or difficulty breathing — allergy to glycerine is rare but not impossible.
Contact a pharmacist or doctor if:
- Dry skin is not improving with regular moisturising, or is cracking, bleeding or intensely itchy — that is a skin condition needing treatment, not just moisture.
- A sore throat lasts more than a week, or comes with high fever, difficulty swallowing or breathing, drooling, or a muffled voice. Difficulty breathing or drooling is an emergency.
- Mouth ulcers last more than three weeks, or keep recurring.
- Earache, discharge or hearing loss develops — do not self-treat an ear that is discharging.
- Constipation lasts more than a couple of weeks, or comes with abdominal pain, vomiting, blood in the stool, unexplained weight loss or a change in bowel habit.
- You have diabetes and cracked or broken skin on your feet. Foot problems in diabetes need proper assessment early.
Related medicine guides
Frequently asked questions
What is glycerine used for? Holding moisture in skin and tissue. It is used in moisturisers, lip and throat products, mouth gels, ear drops, cough mixtures and constipation suppositories.
Is it a medicine? Not in itself. It is a base ingredient with soothing and moisturising properties, and it appears as a component of registered products.
Can I put it straight on my skin? Better diluted, or as part of a formulated cream. Neat glycerine can sting and may feel drying, because it draws water from wherever it can.
Does it treat eczema? No. It moisturises, which helps comfort and the skin barrier, but active eczema usually needs a proper emollient and often a steroid cream.
Can I use it for a sore throat? It soothes and coats, which can be comforting. It does not treat infection. A throat that is not settling in a week needs assessing.
Can I put it in my ear? Only a product intended for ears, and never if the eardrum may be perforated or the ear is discharging. Ask a pharmacist.
How do glycerine suppositories work? They draw water into the rectum and stimulate emptying, usually within about an hour. They are for occasional use, not routine.
Is it safe in pregnancy and for children? Topical use is generally regarded as low risk, and glycerine suppositories are used in children at appropriate sizes — but ask a pharmacist first.